A Dual-Core Wide Bandwidth and High-Accuracy Fluxgate Current Sensor

A novel fluxgate current sensor scheme based on a dual-core configuration is proposed in this study. By integrating a direct current (DC) zero-flux detector, an alternating current (AC) zero-flux detector, and a secondary compensation coil module, a unified design of multi-coil and multi-signal processing circuits is achieved. Compared with conventional three-core fluxgate designs, the proposed approach offers a simplified structure while maintaining high bandwidth and high-accuracy measurement capabilities. A prototype was developed based on the proposed principles, which was subsequently evaluated through experiments. The results demonstrate that the sensor achieves a -3dB bandwidth exceeding 1.6 MHz. Within the frequency range of 10 Hz to 100 kHz, the amplitude response variation remains below 2%, and the phase deviation is within 2°. When benchmarked against a precision shunt resistor, the measurement error of 100 kHz AC current is maintained within 3%. The sensor also exhibits a step-response rise time of approximately 300 ns. These findings indicate that the proposed dual-core fluxgate sensor is well-suited for wideband current measurement applications demanding high dynamic performance and accuracy.